The nrepl server can be used to access the repl when the application is deployed as well

if you set the :nrepl-port in your production environment, then you can connect your editor to it. My team commonly uses this when we deploy our apps to kubernetes, and then we can port forward from there to a local machine

it's quite useful for inspecting the state of the app when troubleshooting things, and sometimes for doing hotfixes

and I there isn't a document describing how the template evolved, but I can answer questions here if you have any specific ones